Because of their high density and small size, modern electronic circuits generate a substantial amount of heat. Complex integrated circuits, especially microprocessors, generate so much heat that they are often unable to operate without a cooling system. Excess heat degrades an integrated circuit's performance and adversely affects its reliability over time. Inadequate cooling causes malfunction in central processing units of personal computers, and may result in system crashes, lockups, unexpected reboots, and other anomalies.
Personal computers have built-in cooling fans. However, smartphones and other handheld electronic devices do not have built-in fans. Moreover, the risk of malfunction is especially severe for the tight confines found inside smartphones and other handheld electronic devices. Heat management is critical as technology advances and newer devices become smaller and more complex, and run at higher power levels and power densities.
There are many use cases in which smartphones get overheated, including gaming, navigation and video conversations. It is common in these use cases for a smartphone to be connected to a charger, in order to avoid battery drainage, and the charging adds additional heat to the device. A smartphone that is not properly cooled reaches a temperature of 70° C.-90° C., which may cause the smartphone to shut down.
The danger of overheating is especially acute when a smartphone is used extensively outdoors or mounted on a dashboard of a car for use as a navigational tool, as a radio or as a video camera, on a hot and sunny day. Conventional approaches suggest use of an external cooling fan or a solar insulator. However, in the situations described above, it is not feasible to mount an external cooling fan near the smartphone since the fan would have to be transported with the smartphone outdoors, or would block a driver's vision if mounted on the dashboard of the car. A solar insulator would prevent only the sun's portion of the heating, but would fail to prevent internal heating.
As such, there is a need to attenuate heat generation for handheld electronic devices.